Apparatus for form-processing paper in a printing press

ABSTRACT

Method for form-processing paper in a printing press by at least one processing tool and a computer includes converting digital data representing desired processing geometries into signals in the computer, and controlling the at least one processing tool with the signals so as to obtain the processing geometries: and apparatus for performing the method.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a division of application Ser. No. 08/564,417, filedon Nov. 29, 1995, now U.S. Pat. No. 5,797,320.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a method and apparatus for form-processingpaper in a printing press by means of at least one processing tool. Whatis meant herein by form-processing is the forming of scores, creases,perforations or the like in the paper.

It has become known heretofore for such forming tools as cutting orscoring tools or perforating tools to be integrated into a printingpress, so that the paper, after being printed, need not be separatelycut to size or prepared for folding., The textbook entitled Maschinenbau[Machine Construction], VEB Verlag Technik Berlin 1968, Vol. 3/II,Chapter 1.5.3.5, pages 597-598, for example, shows a combined printingpress and punching machine.

If a new printing job is to be performed with such a machine, generallythe processing tools must be changed, or at least adjusted.

2. Summary of the Invention

It is accordingly an object of the invention to permit rapid andeconomical variation of processing geometries when form-processing paperin a printing press.

With the foregoing and other objects in view, there is provided, inaccordance with the invention, a method for form-processing paper in aprinting press by means of at least one processing tool and a computer,which comprises converting digital data representing desired processinggeometries into signals in the computer, and controlling the at leastone processing tool with the signals so as to obtain the processinggeometries.

In accordance with another mode of the method according to theinvention, the form-processing includes at least one of the processes ofcutting, perforating, scoring and stitching.

In accordance with a further mode, the method according to the inventionincludes separately generating with the printing press the digital datafor representing the processing geometries, and then transmitting thedata to the printing press computer for calculating the control signalsfor the at least one processing tool.

In accordance with an added mode of the method according to theinvention, the generation of the digital data is performed within thecontext of the printed product design in an electronic printingprecursor stage, and the method includes adding color information to thedigital data in a manner that one color, respectively, is assigned toeach type of processing.

In accordance with an additional mode of the method according to theinvention, the generation of the digital data in the printing precursorstage is in the form of postscript data, and the method includesconverting the postscript data into a pixel pattern including at leastone pixel pattern for one color to be printed and at least one pixelpattern which has a color assigned to one type of processing, andcalculating in the printing press computer the control signals for thecorresponding processing tool from the at least one pixel pattern.

In accordance with yet another mode, the method according to theinvention includes defining a plurality of zones along the width of theprinting press, assigning at least one processing tool to each of thezones and, during operation of the printing press, positioning andactivating and deactivating the processing tools in a manner required byprocessing geometries in the corresponding zone.

In accordance with yet a further mode of the method according to theinvention, the form-processing is performed with at least one beam oflight, and the method comprises either tracking the contours to beform-processed or linearly scanning the surface of the paper, includingturning the light beam on only at the contours to be form-processed.

In accordance with yet an added mode, the method according to theinvention includes imprinting the geometry to be form-processed prior toprocessing with a color which absorbs the light used for the processing.

In accordance with yet an additional mode, the method according to theinvention includes generating the light by laser.

In accordance with another aspect of the invention, there is provided anapparatus for form-processing paper in a printing press having at leastone paper form-processing tool disposed adjacent to a paper path,comprising a computer having an input for digital data representingdesired processing geometries and an output for control signals, the atleast one processing tool being operatively connected to the computerand being activatable and deactivatable by the control signals, the atleast one processing tool being positionable at least in part along thewidth of the printing press.

In accordance with another feature of the invention, the at least onepaper form-processing tool is selected from the group consisting of amechanical cutting tool, a perforating tool, a scoring tool and astitching tool, and a water-jet cutting device.

In accordance with a further feature of the invention, the at least onepaper form-processing tool is selected from the group consisting of afocused beam of light, a laser, and a laser optical element.

In accordance with an added feature of the invention, the apparatusincludes a plurality of zones defined along the width of the printingpress, and a plurality of the paper form-processing tools disposed alongthe width of the printing press and, respectively, assigned to each ofthe zones.

In accordance with an additional feature of the invention, the pluralityof paper form-processing tools form a paper form-processing unitmountable on the printing press.

In accordance with yet another feature of the invention, the paperform-processing unit has a laser diode array extending over the width ofthe printing press.

In accordance with yet a further feature of the invention, the laserdiode array is stationary, and at least one optical element is disposedbetween the laser diode array and a surface of paper.

In accordance with yet an added feature of the invention, the at leastone optical element focuses light from at least one diode of the diodesof the laser diode array onto at least one focal point located on thepaper.

In accordance with a concomitant feature of the invention, the at leastone optical element is movable crosswise to the paper path.

By the foregoing provisions, the pressman is relieved of the task ofarranging the processing tools to fit the printing job. Thecorresponding make-ready or conversion times are eliminated. The digitaldata for defining the geometry can be generated by means of availablesoftware and hardware which is used for designing the printed product inthe electronic printing precursor stage. In other words, type-settingand the defining of the geometry can be performed in a single operation,and the processing task can subsequently be performed largelyautomatically.

In an apparatus for form-processing paper in a printing press having atleast form-processing tool disposed adjacent to the paper path, theforegoing object is attained in accordance with the invention in thatthe at least one processing tool is activatable and deactivatable bymeans of the control signals and can at least in part be positionedalong the width of the printing press, and a computer is provided whichhas an input for digital data representing desired processing geometriesand an output for the control signals.

For greater freedom in construction or design and for higher processingspeed, preferably a plurality of optionally different types ofform-processing tools are used over the entire width of the paper, eachof the tools being positionable and activatable and deactivatable,respectively, within an assigned zone along the width of the machine bymeans of the control signals.

Particularly great construction or design freedom is obtained if theprocessing is performed by focused light, for example, of the typeproduced by lasers; in that case, rounded corners and other filigreedcontours can be produced quite easily. Compared with a combined printingpress and punching machine with a male and female punching die, thecopies printed on one sheet of paper to be printed can be spaced closertogether, and the yield of imprinted material is greater, because noforces or only very slight forces, respectively, of separation andexpulsion act perpendicularly to the surface of the imprinted material,and thus the stabilizing function of the skeleton formed by thetrimmings is dispensed with.

It is true that cutting paper by laser has become conventional; see forexample the article, “Papierschneiden mit Laser” [Paper Cutting byLaser] by H. Federle and S. Keller in the journal, Papier undKunststoff-Verarbeiter [Paper and Plastics Processor], Number 9/92,pages 54-59. The versatility of laser cutting devices is of particularsignificance, however, if it is used in combination with printingpresses as in the invention. Because digital data which represent theprocessing geometries can be produced in combination with thetypesetting, and it is no longer necessary to make adjustments to theprinting press itself, the invention makes it possible to form-processpaper in a printing press with immediately variable processinggeometries. Small runs of printed products which require complicatedform-processing thus become considerably more economical. This is trueto an even greater extent for digital printing presses which can be usedas page printers because, with the invention, it is even possible foreach page to undergo an individualized form-processing withoutimpairment of the printing speed.

In digital printing presses, the method and apparatus according to theinvention can moreover be achieved especially simply. For example, ifthe printing press computer already includes an RIP (raster imageprocessor), which breaks down the digital data, generated as postscriptdata and representing the pixels and the colors thereof, into pixelpatterns for the colored partial images then, in the printing precursorstage, the processing geometries and the kinds of form-processing areshown in the same format as the pixels and image colors. The softwarenormally used in typesetting offers suitable capabilities foraccomplishing this; one example is identifying one processing geometryand one type of form-processing by means of a frame having a color whichis defined as a special color designated as “cutting”. Because theprocessing geometries and types of form-processing are handled likespecial colors, the RIP generates a special pixel pattern for each kindof form-processing; this pattern is then suitably interpreted by theprinting press computer and converted into the control signals for theform-processing tools.

Accordingly, to use the invention in a digital printing press, all thatis needed is to provide a unit for actually performing theform-processing task. Otherwise, the existing devices and controlmethods can be used. Even older printing presses, however, can beretrofitted with such a unit without difficulty. The pixel patterns forthe processing geometries are produced in this case in the RIP of atypesetting computer, for example. Moreover, lasers are not the onlysuitable form-processing tools. Given a suitable arrangement andcombination, thoroughly flexible form-processing can be accomplishedwith mechanical processing tools.

On the other hand, in the case of contactless processing, for exampleusing a laser, a further mode of the method according to the inventionmay be considered, which is for the geometry which is to cut, forexample, to be preprinted using a light-absorbent printing ink, beforeperforming the form-processing. The color may be black, for example, ormay be visually imperceptible, as long as its light absorption is tunedto the spectrum of the cutting light and at least partially coincidestherewith. Preprinting the cutting geometry has the followingadvantages: a defined absorption of the laser light is attained, whichminimizes the influence upon the cutting capacity of the material to beimprinted, and thus minimizes the necessary adjustments and adaptationsof the light parameters to the substrate; the cutting capacity is betterbecause of the higher energy yield; a perforation need not be generatedby modulating the beam of light; instead, it can be produced by means ofa suitably preprinted broken line and a constant light incidence,thereby reducing the computer capacity and control expenditure required;the beam of light need not be focused precisely at the surface of thepaper, so there is less vulnerability in terms of spacing distance andthus less tolerance to fluttering of the paper, for example; and thetracking of the beam need not be so exact.

Because less stringent demands are made with respect to focusing andbecause of the defined light absorption, it is, moreover, not absolutelynecessary to use lasers for form-processing preprinted processinggeometries; instead, conventional light sources can also be considered.

Other features which are considered as characteristic for the inventionare set forth in the appended claims.

Although the invention is illustrated and described herein as embodiedin apparatus for form-processing paper in a printing press, it isnevertheless not intended to be limited to the details shown, sincevarious modifications and structural changes may be made therein withoutdeparting from the spirit of the invention and within the scope andrange of equivalents of the claims.

The construction and method of operation of the invention, however,together with additional objects and advantages thereof will be bestunderstood from the following description of specific embodiments whenread in connection with the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1a and 1 b are diagrammatic side elevational views of a printingpress illustrating two options for installing a paper form-processingunit therein;

FIG. 2 is a basic diagrammatic and schematic perspective view of thelayout of the paper form-processing unit;

FIG. 3 illustrates schematically a method for guiding a beam in alaser-beam sheet form-processing tool;

FIG. 4 illustrates schematically the use of a laser diode array for thesheet form-processing; and

FIGS. 5a to 5 c illustrate schematically and diagrammatically threedifferent optical elements for generating different beam characteristicsin a laser diode array.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings and, first, particularly to FIGS. 1a and 1b thereof, there are shown diagrammatically therein respective paperform-processing units 1 which are integratable into an existing printingpress module, such as a delivery device 2 in FIG. 1a, or may be acomponent of a separate processing section 3 which, in FIG. 1b, isprovided between the delivery 2 and a printing unit 4. Althoughsheet-fed offset printing presses, in particular, have been shown inFIGS. 1a and 1 b, the paper form-processing unit 1 may also be used inother kinds of printing presses.

As shown in FIG. 2, the processing unit 1 includes a number ofprocessing tools 5, which are disposed in a row crosswise to a papertravel direction R. The processing tools 5, in the embodiment of theinvention shown in FIG. 2, are laser light sources or output opticalelements of laser light sources, the laser beams of which can be aimedtowards various locations of the paper 6 by non-illustrated devices forbeam deflection, or by mechanical laser head movements. Crosswise to thepaper travel direction R, i.e., along the width B of the paper, therespective processing tools 5 sweep over one zone Z, the zones Zadjoining one another crosswise to the paper travel direction R andextending over the maximum possible paper width B or the working widthof the printing press. The zones Z may also, however, overlap oneanother entirely or in part, or free zones without any processing toolassociated therewith may be provided. The laser beams of the processingtools 5 can be guided not only with-in a given zone Z but also within asection A in the paper travel direction R, in order to be able toperform cutting motions which are directed perpendicularly to the papertravel direction R or counter to the paper travel.

The processing tools 5 which use laser light are suitable forselectively cutting, perforating, and scoring the paper 6. These andother types of processing can be achieved not only with lasers, whichoperate in contactless fashion, but also with mechanical processingtools, which must be capable of being positioned above the surface ofthe paper, and activated and deactivated, by means of control signals,so that the method described hereinbelow can be employed.

The preferred mode of the method for paper form-processing in accordancewith the invention includes the following three partial steps, which aredescribed hereinafter: definition of the processing geometries, in theprinting precursor stage; data transfer to the printing press andinterpretation of the data; and performing the processing task.

In the designing of a printed product in the electronic printingprecursor stage, the processing geometries are defined using the designtools of the appropriate software. In such programs, one freely definedand designated color can be assigned to the frame of a square, forexample. In the defining of a particular geometry, an arbitrary color isselected for that geometry and is designated as “perforating”,“scoring”, or “cutting”, for example. On the screen used for electronictypesetting, the geometry appears in the color defined by the user. Thepostscript data generated by the electronic typesetting then include notonly the picture information for the actual printing but also one ormore processing geometries and a respective “color name” for theassociated kind of processing.

The postscript data are transmitted to a digital printing press andseparated in an RIP (raster image processor) into the color componentsC, M, Y and K, i.e., cyan, magenta, yellow and black, in the case offour-color printing, by being converted into individual pixel patterns(bit maps). A color for a processing geometry defined in a printingprecursor stage is handled by the RIP like a special color, and the RIPaccordingly prepares one additional, separate bit map for all theprocessing geometries, such as “square”, etc., per type of processing,such as “cutting”, “perforating”, and so forth. From the bit maps forthe color components, the printing press computer generates the controlparameters for the image printing units and ink supplies. From the bitmaps for the processing geometries, which are easily detected orinterpreted as such from the identification by means of special colors,the printing press computer also calculates the control signals for theprocessing tools. Optionally, even other supplementary data, whichcannot yet have been defined in the printing precursor stage, such asfor the thickness of the paper, for example, can be input into theprinting press computer.

The control signals calculated as described hereinabove are thensupplied to the processing unit 1 and the processing tools 5 thereof,respectively, so that the processing tasks can be performed. Via controllines, the computer, which converts the information from the bit mapsinto the control signals, also receives adjustment values, such as thenumber and the basic positions of the processing tools 5, for example,and takes them into account in performing the conversion into thecontrol signals.

If the processing tools 5 are lasers, as in FIG. 2, the cutting motionof the lasers is then preferably performed by one of two conventionalmethods.

In one method, the beam follows the contour to be cut (vector scanning)and, accordingly, undercuts in the paper travel direction R, and cutsperpendicular to the paper travel direction R are realizable. Aperforation is produced by periodically turning the laser on and off.

The other method, schematically shown in FIG. 3, is that the entireprocessing region of a zone Z is scanned linearly (raster scanning) and,by briefly turning on the laser, the paper 6 traveling therebeneath ispunctured only along the cutting contour. A scanning direction C and thepaper travel direction R can then extend at an arbitrary angle to oneanother.

In a further embodiment, a laser diode array 7 extending over the widthof the printing press is secured in the processing unit 1, this array,in practice, being composed of individual modules. In the interest ofsimplicity, in FIG. 4, only four diodes 8 of the laser diode array 7have been shown. The diodes 8, or in a non-illustrated alternative,fiber-optical waveguides, which bring the light in from diodes locatedfarther away, have a center-to-center spacing of approximately 0.1 to0.2 mm. The gap width of a cut on the paper 6 is preferably from 0.05 to0.1 mm.

The laser light either shines directly on the paper 6, or the light of aplurality of diodes 8 is focused by an optical element 9, which is alens in the embodiment of FIG. 4, onto one or more focal points 10.Three different embodiments of such an optical element 9 are shown inFIGS. 5a to 5 c, and provision may be made for being able to switch backand forth among these or other suitable variants.

The embodiment shown in FIG. 5a, for focusing the light of a pluralityof diodes 8 onto a focal point 10 by means of the optical element 9, isused whenever relatively high light outputs are needed in order to severthick materials which are being imprinted, the number of combined diodes8 then being selected accordingly.

The embodiment shown in FIG. 5b, for focusing the light of a respectivediode 8 by means of an optical element 9′ composed of a plurality oflens elements, is used whenever thin materials which are being imprintedare to be cut apart, or thick materials which are being imprinted are tobe scored (indented).

The embodiment of FIG. 5c has an optical element 9″ with which the paper6 can be cut apart and scored in a single operation by employing thevariant embodiments of FIG. 5a and FIG. 5b in parallel.

To permit a crosswise or transverse movement of the focal point 10despite a stationary laser diode array 7, a non-illustrated arrangementis provided with which the optical element 9 can be moved crosswise tothe paper travel direction R (FIG. 4) and relative to the diodes 8.Provision is made therein for a plurality of optical elements 9 per zoneto be disposed in front of the laser diode array 8.

In all of the aforedescribed modes of the method for beam guidance andvariant embodiments for beam focusing, the light absorption and, thus,the cutting output are improved if the geometry to be cut is preprintedwith a light-absorbent color. This is very simple to do; for example,the printing press computer interprets the pixel pattern of theprocessing geometry also as the pixel pattern of an image having apreprinted color matching it. A number of additional advantages andcapabilities afforded by preprinting the processing geometries havealready been mentioned hereinbefore.

The method and corresponding apparatus which have been described abovethus permit on-line, further paper processing of various types (such ascutting or scoring) in a printing press over the entire printing andpaper width, respectively, with freely designable and immediatelyvariable processing geometries.

We claim:
 1. An apparatus for cutting a printing material in a printingpress to any desired, curved or straight, two-dimensional geometry formwith reference to a printing surface of the printing material,comprising: a computer having an input for digital data representing thedesired, curved or straight, two-dimensional geometry form and an outputfor control signals; at least one printing material cutting tool beingmounted on output side of the printing press and operatively connectedto said computer and controlled by said control signals, said at leastone printing material cutting tool using a laser diode for cutting theprinting material to the desired, curved or straight, two-dimensionalgeometric form.
 2. Apparatus according to claim 1, including astationary laser diode array extending over a width of said printingpress, said laser diode is a part of said stationary laser diode array.3. Apparatus according to claim 1, including a plurality of zonesdefined along the width of the printing press, and a plurality of theprinting material cutting tools disposed along the width of the printingpress and, respectively, assigned to each of said zones.
 4. Apparatusaccording to claim 1, wherein said laser diode array is stationary, andat least one optical element is disposed between said laser diode arrayand a surface of said printing material.
 5. Apparatus according to claim4, wherein said at least one optical element focuses light from at leastone diode of the diodes of the laser diode array onto at least one focalpoint located on said printing material.
 6. Apparatus according to claim4, wherein said at least one optical element is movable crosswise to theprinting material path.
 7. An apparatus for cutting a printing materialin a printing press to any desired, curved or straight, two-dimensionalgeometry form with reference to a printing surface of the printingmaterial, comprising: a printing press for preprinting a printingmaterial using a light absorbent printing ink; a computer having aninput for digital data representing the desired, curved or straight,two-dimensional geometry form and an output for control signals; and atleast one printing material cutting tool being operatively connected tosaid computer and controlled by said control signals, said at least oneprinting material cutting tool being mounted on an output side of saidprinting press and outputting a cutting light for cutting the printingmaterial to the desired, curved or straight, two-dimensional geometricform.
 8. The apparatus according to claim 7, wherein only the desiredtwo-dimensional geometric form is preprinted on the printing material.9. The apparatus according to claim 7, wherein said light absorbentprinting ink has a light absorption which at least partially coincideswith a spectrum of said cutting light.
 10. The apparatus according toclaim 7, wherein said printing material cutting tool is a laser diode.11. The apparatus according to claim 7, wherein said printing materialcutting tool is a stationary laser diode array having a plurality oflaser diodes.
 12. The apparatus according to claim 11, including aplurality of zones defined along a width of the printing press, and eachlaser diode of said plurality of laser diodes being disposed along awidth of said printing press and, respectively, assigned to each of saidzones.
 13. The apparatus according to claim 12, including at least oneoptical element focuses light from at least one laser diode of saidplurality of diodes onto at least one focal point located on theprinting material.
 14. The apparatus according to claim 13, wherein saidat least one optical element is movable crosswise to a printing materialpath.